Due to climate change, extreme heat stress events have become more frequent, adversely affecting rice yield and grain quality. The accumulation and translocation of dry matter and nitrogen substances are essential for...Due to climate change, extreme heat stress events have become more frequent, adversely affecting rice yield and grain quality. The accumulation and translocation of dry matter and nitrogen substances are essential for rice yield and grain quality. To assess the impact of high temperature stress(HTS) at the early panicle initiation(EPI) stage on the accumulation, transportation, and distribution of dry matter and nitrogen substances in various organs of rice, as well as the resulting effects on rice yield and grain quality, pot experiments were conducted using an indica rice cultivar Yangdao 6(YD6) and a japonica rice cultivar Jinxiangyu 1(JXY1) under both normal temperature(32 ℃/26 ℃) and high temperature(38 ℃/29 ℃) conditions. The results indicated that exposure to HTS at the EPI stage significantly decreased rice yield by reducing spikelet number per panicle, grain-filling rate, and grain weight. However, it improved the nutritional quality of rice grains by increasing protein and amylose contents. The reduction in nitrogen and dry matter accumulation accounted for the changes in spikelet number per panicle, grain-filling rate, and grain size. Under HTS, the decrease in nitrogen accumulation accompanied by the reduction in dry matter may be due to the down-regulation of leaf net photosynthesis and senescence, as evidenced by the decrease in nitrogen content. Furthermore, the decrease in sink size limited the translocation of dry matter and nitrogen substances to grains, which was closely related to the reduction in grain weight and the deterioration of grain quality. These findings significantly contribute to our understanding of the mechanisms of HTS on grain yield and quality formation from the perspective of dry matter and nitrogen accumulation and translocation. Further efforts are needed to improve the adaptability of rice varieties to climate change in the near future.展开更多
Macroporous 3D carbon doped with nitrogen confined Mo catalyst(MoO_(x)@CN)had been prepared by a facile one-step pyrolysis technique using silica as a template and was employed for oxidative desulfurization(ODS)of dib...Macroporous 3D carbon doped with nitrogen confined Mo catalyst(MoO_(x)@CN)had been prepared by a facile one-step pyrolysis technique using silica as a template and was employed for oxidative desulfurization(ODS)of dibenzothiophene(DBT)in model fuel with H2O_(2) as oxidant.The effect of different ope rating conditions(i.e.,reaction te mperature and time,catalyst dosage,H2O_(2)/DBT(O/S)molar ratio)were also systematic investigated.Under the optimal reaction condition,MoO_(x)@CN catalyst exhibited highly excellent ODS performance toward DBT,the highest sulfur removal efficiency can be up to 99.9%and sulfur content was wiped out from 800 ppm to 10 ppm.Due to the robust 3D structure promoting rapid transfer,in addition to the increased number of active sites induced by the Mo vacancies,the catalyst,prepared using chitosan and ammonium heptamolybdate in a mass ratio of 1:0.5,displayed rapid kinetics and low activation energy in the oxidation of dibenzothiophene.Moreover,it exhibited excellent recyclability after five cycles without any obvious decrease in catalytic activity for the oxidative desulfurization reaction.展开更多
In order to research effects of the nitrogen top-dressing levels on carbon-nitrogen metabolism and yield of Desmodium styracifolium, a field experiment was conducted on the research farm of Guangxi University in 2007....In order to research effects of the nitrogen top-dressing levels on carbon-nitrogen metabolism and yield of Desmodium styracifolium, a field experiment was conducted on the research farm of Guangxi University in 2007. Some physiological indexes and yield ofD. styracifolium were compared among five nitrogen top-dressing levels （0, 37.5, 75.0, 112.5 and 150.0 kg N. hm-2）. Results showed that the nitrogen top-dressing could significantly increase the contents of chlorophyll, soluble protein, sucrose and nitrogen as well as nitrate reducase activity. However, there were no significant differences in most of these indexes under high nitrogen levels. Consistently, there was no significant difference in yield among nitrogen top-dressing levels of 75 kg N.hm-2, 112.5 kg N. hm-2 and 150 kg N-hm-2. Therefore, the optimum nitrogen top-dressing level ofD. styracifolium was 75 kg N. hm-2.展开更多
This study was conducted to elucidate the regulating mechanism of sodium nitroprussiate on seed germination and seedling growth of cherry tomato. After the treatment with different concentrations of sodium nitroprussi...This study was conducted to elucidate the regulating mechanism of sodium nitroprussiate on seed germination and seedling growth of cherry tomato. After the treatment with different concentrations of sodium nitroprusside, the effects on the metabolites and key enzyme activities in carbon-nitrogen metabolism of cherry tomato cuhivar Zhuyun as an experimental material were investigated. The results showed that from seed germination to seedling period, the contents of starch and total nitrogen decreased, but the contents of soluble sugar, reducing sugar, sucrose and soluble protein increased firstly and then decreased; and free amino acids content increased gradually. Sodium nitroprusside made the contents of starch, sucrose and free amino acids higher than CK. From seed germination to seedling period in cherry tomato, the activities of amylase, glutamine synthetase （GS） and sucrose phosphate synthase （SPS） decreased; the activities of nitrate reductase （NR） and glutamate synthase （GOGAT） increased at first and decreased then; and the CK and the 0.25 mmol/L sodium nitroprusside treatments exhibited de- creased sucrose synthase （SS） activity, and the trend was increasing at first and decreasing then after the treatment with 0.50 and 1.00 mmol/L sodium nitroprus- side. Sodium nitroprusside treatment improved amylase activity; and the carbon-nitrogen ratio of the CK increased at first and decreased then, while the values of other treatments tended to decrease. In addition, sodium nitroprusside did not affect seed germination potential and germination rate, but significantly improved biomass accumulation, root length and height of seedlings. These data suggest that sodium nitroprusside could affect the conversion of starch and sugar accumulation, delay the decomposition of total nitrogen and soluble protein, and achieve the effects of accelerating the accumulation of free amino acids, and promoting seed germination and seedling growth, and 0.50 mmol/L sodium nitroprusside has the best effect.展开更多
Circularly polarized luminescence(CPL)materials are essential for advanced optoelectronic applications,yet efficient chiral design strategies remain challenging.Axial chirality has been widely employed in the construc...Circularly polarized luminescence(CPL)materials are essential for advanced optoelectronic applications,yet efficient chiral design strategies remain challenging.Axial chirality has been widely employed in the construction of CPL materials due to its unique rigid structure.However,the focus has been primarily on the derivatives of carbon-carbon axial chirality.We herein propose a strategy for constructing carbon-nitrogen(C─N)axially chiral molecular frameworks to fully exploit the excellent chromophoric properties of nitrogen-containing heterocycles(such as carbazole).A pair of chiral emitters,(S/R)-AI-2TCFC,was designed and synthesized,exhibiting an emission peak at 578 nm both in the toluene solution and in the neat film state.It possessed typical aggregation-induced emission(AIE),thermally activated delayed fluorescence(TADF),and a luminescence dissymmetry factor(glum)of 10^(-3),demonstrating its potential for high-performance device applications.These materials were successfully applied in circularly polarized organic light-emitting diodes(CP-OLEDs),demonstrating promising electroluminescence performance.This innovative strategy not only expands the design toolbox for CPL materials but also paves the way for next-generation high-performance optoelectronic devices.展开更多
Aims Carbon(C)sequestration in terrestrial ecosystems is strongly regulated by nitrogen(N)processes.However,key parameters that determine the degree of N regulation on terrestrial C sequestration have not been well qu...Aims Carbon(C)sequestration in terrestrial ecosystems is strongly regulated by nitrogen(N)processes.However,key parameters that determine the degree of N regulation on terrestrial C sequestration have not been well quantified.Methods Here,we used a Bayesian probabilistic inversion approach to estimate 14 target parameters related to ecosystem C and N interactions from 19 datasets obtained from Duke Forests under ambient and elevated carbon dioxide(CO_(2)).Important FindingsOur results indicated that 8 of the 14 target parameters,such as C:N ratios in most ecosystem compartments,plant N uptake and external N input,were well constrained by available datasets whereas the others,such as N allocation coefficients,N loss and the initial value of mineral N pool were poorly constrained.Our analysis showed that elevated CO_(2)led to the increases in C:N ratios in foliage,fine roots and litter.Moreover,elevated CO_(2)stimulated plant N uptake and increased ecosystem N capital in Duke Forests by 25.2 and 8.5%,respectively.In addition,elevated CO_(2)resulted in the decrease of C exit rates(i.e.increases in C residence times)in foliage,woody biomass,structural litter and passive soil organic matter,but the increase of C exit rate in fine roots.Our results demonstrated that CO_(2)enrichment substantially altered key parameters in determining terrestrial C and N interactions,which have profound implications for model improvement and predictions of future C sequestration in terrestrial ecosystems in response to global change.展开更多
甘薯是我国重要的粮食与经济作物,高氮环境下容易茎叶旺长而造成产量和品质的降低。本研究以不易徒长的品种徐薯32号和易徒长的品种徐紫薯8号为试验材料,设置不同施氮肥水平(0、80和200 kg hm–2)处理,测定甘薯徒长表型和碳氮含量变化,...甘薯是我国重要的粮食与经济作物,高氮环境下容易茎叶旺长而造成产量和品质的降低。本研究以不易徒长的品种徐薯32号和易徒长的品种徐紫薯8号为试验材料,设置不同施氮肥水平(0、80和200 kg hm–2)处理,测定甘薯徒长表型和碳氮含量变化,通过转录组测序进行相关代谢途径和徒长候选基因挖掘分析,并对测序结果进行RT-qPCR验证。结果表明,与徐薯32号相比,高氮处理下徐紫薯8号的地上部生长更加旺盛,块根产量显著降低,徒长情况严重。高氮处理使2个品种茎尖的氮含量增加而可溶性糖含量降低,碳氮代谢途径的基因表达量显著提高,徐紫薯8号茎尖的碳氮代谢变化更加显著,地上部易受高氮影响。转录组测序表明,正常施氮和高氮处理间存在差异表达基因3852个,对2个品种共同筛选到的1174个差异表达基因进行GO与KEGG通路富集分析,发现差异基因在损伤响应、茉莉酸响应、氨基酸代谢、玉米素生物合成等途径被显著富集,不同甘薯品种对高氮可能存在共同的响应机制。相同处理下,徐薯32号和徐紫薯8号间差异表达基因共6998个,对高氮处理筛选到而正常施氮未筛选到的1186个差异表达基因进行GO与KEGG通路富集分析,发现差异基因在类异戊二烯代谢、激素应答、细胞色素P450、氮代谢、玉米素生物合成等途径被显著富集,进一步筛选到6个甘薯高氮徒长的候选基因(g9506.t1、g14945.t1、g37255.t1、g25587.t1、g7821.t1和g18076.t1)。本研究为解析甘薯高氮徒长的生理机制提供了理论支持,也为选育耐高氮甘薯品种提供了基础。展开更多
基金supported by the Jiangsu Agriculture Science and Technology Innovation Fund,China(Grant No.CX(23)1035)the National Natural Science Foundation of China(Grant Nos.32201888,32071943,and 32272197)+2 种基金the Provincial Natural Science Foundation of Jiangsu,China(Grant No.BK20200923)the National Key Research and Development Program of China(Grant Nos.SQ 2022YFD1500402 and SQ2022YFD2300304)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China.
文摘Due to climate change, extreme heat stress events have become more frequent, adversely affecting rice yield and grain quality. The accumulation and translocation of dry matter and nitrogen substances are essential for rice yield and grain quality. To assess the impact of high temperature stress(HTS) at the early panicle initiation(EPI) stage on the accumulation, transportation, and distribution of dry matter and nitrogen substances in various organs of rice, as well as the resulting effects on rice yield and grain quality, pot experiments were conducted using an indica rice cultivar Yangdao 6(YD6) and a japonica rice cultivar Jinxiangyu 1(JXY1) under both normal temperature(32 ℃/26 ℃) and high temperature(38 ℃/29 ℃) conditions. The results indicated that exposure to HTS at the EPI stage significantly decreased rice yield by reducing spikelet number per panicle, grain-filling rate, and grain weight. However, it improved the nutritional quality of rice grains by increasing protein and amylose contents. The reduction in nitrogen and dry matter accumulation accounted for the changes in spikelet number per panicle, grain-filling rate, and grain size. Under HTS, the decrease in nitrogen accumulation accompanied by the reduction in dry matter may be due to the down-regulation of leaf net photosynthesis and senescence, as evidenced by the decrease in nitrogen content. Furthermore, the decrease in sink size limited the translocation of dry matter and nitrogen substances to grains, which was closely related to the reduction in grain weight and the deterioration of grain quality. These findings significantly contribute to our understanding of the mechanisms of HTS on grain yield and quality formation from the perspective of dry matter and nitrogen accumulation and translocation. Further efforts are needed to improve the adaptability of rice varieties to climate change in the near future.
基金the Applied Basic Research Project of Science and Technology Department of Sichuan Province(No.2020YJ0418)。
文摘Macroporous 3D carbon doped with nitrogen confined Mo catalyst(MoO_(x)@CN)had been prepared by a facile one-step pyrolysis technique using silica as a template and was employed for oxidative desulfurization(ODS)of dibenzothiophene(DBT)in model fuel with H2O_(2) as oxidant.The effect of different ope rating conditions(i.e.,reaction te mperature and time,catalyst dosage,H2O_(2)/DBT(O/S)molar ratio)were also systematic investigated.Under the optimal reaction condition,MoO_(x)@CN catalyst exhibited highly excellent ODS performance toward DBT,the highest sulfur removal efficiency can be up to 99.9%and sulfur content was wiped out from 800 ppm to 10 ppm.Due to the robust 3D structure promoting rapid transfer,in addition to the increased number of active sites induced by the Mo vacancies,the catalyst,prepared using chitosan and ammonium heptamolybdate in a mass ratio of 1:0.5,displayed rapid kinetics and low activation energy in the oxidation of dibenzothiophene.Moreover,it exhibited excellent recyclability after five cycles without any obvious decrease in catalytic activity for the oxidative desulfurization reaction.
基金Supported by Scientifi c Research Foundation of Guangxi University (x061106)
文摘In order to research effects of the nitrogen top-dressing levels on carbon-nitrogen metabolism and yield of Desmodium styracifolium, a field experiment was conducted on the research farm of Guangxi University in 2007. Some physiological indexes and yield ofD. styracifolium were compared among five nitrogen top-dressing levels （0, 37.5, 75.0, 112.5 and 150.0 kg N. hm-2）. Results showed that the nitrogen top-dressing could significantly increase the contents of chlorophyll, soluble protein, sucrose and nitrogen as well as nitrate reducase activity. However, there were no significant differences in most of these indexes under high nitrogen levels. Consistently, there was no significant difference in yield among nitrogen top-dressing levels of 75 kg N.hm-2, 112.5 kg N. hm-2 and 150 kg N-hm-2. Therefore, the optimum nitrogen top-dressing level ofD. styracifolium was 75 kg N. hm-2.
基金Supported by National Natural Science Foundation of China(31660559)Scientific Research Project of Kunming University(XJZZ1604)Open Fund of Key Laboratory of Special Biological Resource Development and Utilization of Universities in Yunnan Province(GXKJ201615)
文摘This study was conducted to elucidate the regulating mechanism of sodium nitroprussiate on seed germination and seedling growth of cherry tomato. After the treatment with different concentrations of sodium nitroprusside, the effects on the metabolites and key enzyme activities in carbon-nitrogen metabolism of cherry tomato cuhivar Zhuyun as an experimental material were investigated. The results showed that from seed germination to seedling period, the contents of starch and total nitrogen decreased, but the contents of soluble sugar, reducing sugar, sucrose and soluble protein increased firstly and then decreased; and free amino acids content increased gradually. Sodium nitroprusside made the contents of starch, sucrose and free amino acids higher than CK. From seed germination to seedling period in cherry tomato, the activities of amylase, glutamine synthetase （GS） and sucrose phosphate synthase （SPS） decreased; the activities of nitrate reductase （NR） and glutamate synthase （GOGAT） increased at first and decreased then; and the CK and the 0.25 mmol/L sodium nitroprusside treatments exhibited de- creased sucrose synthase （SS） activity, and the trend was increasing at first and decreasing then after the treatment with 0.50 and 1.00 mmol/L sodium nitroprus- side. Sodium nitroprusside treatment improved amylase activity; and the carbon-nitrogen ratio of the CK increased at first and decreased then, while the values of other treatments tended to decrease. In addition, sodium nitroprusside did not affect seed germination potential and germination rate, but significantly improved biomass accumulation, root length and height of seedlings. These data suggest that sodium nitroprusside could affect the conversion of starch and sugar accumulation, delay the decomposition of total nitrogen and soluble protein, and achieve the effects of accelerating the accumulation of free amino acids, and promoting seed germination and seedling growth, and 0.50 mmol/L sodium nitroprusside has the best effect.
基金supported by the China Postdoctoral Science Foundation(2023M743353 and 2024T170890)the National Natural Science Foundation of China(22401241,52303382,52273197,52333007,and 22275040)+3 种基金the National Key Research and Development Program of China(2023YFB3810001)Shenzhen Key Laboratory of Functional Aggregate Materials(ZDSYS20211021111400001)the Science,Technology,and Innovation Commission of Shenzhen Municipality(KQTD20210811090142053,GJHZ20210705141810031,JCYJ20220818103007014,JCYJ20220530143805012,and JCYJ20210324134613038)theInnovation and Technology Commission(ITC-CNERC14SC01).
文摘Circularly polarized luminescence(CPL)materials are essential for advanced optoelectronic applications,yet efficient chiral design strategies remain challenging.Axial chirality has been widely employed in the construction of CPL materials due to its unique rigid structure.However,the focus has been primarily on the derivatives of carbon-carbon axial chirality.We herein propose a strategy for constructing carbon-nitrogen(C─N)axially chiral molecular frameworks to fully exploit the excellent chromophoric properties of nitrogen-containing heterocycles(such as carbazole).A pair of chiral emitters,(S/R)-AI-2TCFC,was designed and synthesized,exhibiting an emission peak at 578 nm both in the toluene solution and in the neat film state.It possessed typical aggregation-induced emission(AIE),thermally activated delayed fluorescence(TADF),and a luminescence dissymmetry factor(glum)of 10^(-3),demonstrating its potential for high-performance device applications.These materials were successfully applied in circularly polarized organic light-emitting diodes(CP-OLEDs),demonstrating promising electroluminescence performance.This innovative strategy not only expands the design toolbox for CPL materials but also paves the way for next-generation high-performance optoelectronic devices.
基金financially supported by US National Science Foundation(NSF)(DEB 0743778,DEB 0840964,DBI 0850290 and EPS 0919466)Office of Science(BER)+1 种基金Department of Energy(DE-FG02-006ER64319)idwestern Regional Center of the National Institute for Climatic Change Research at Michigan Technological University(DE-FC02-06ER64158).
文摘Aims Carbon(C)sequestration in terrestrial ecosystems is strongly regulated by nitrogen(N)processes.However,key parameters that determine the degree of N regulation on terrestrial C sequestration have not been well quantified.Methods Here,we used a Bayesian probabilistic inversion approach to estimate 14 target parameters related to ecosystem C and N interactions from 19 datasets obtained from Duke Forests under ambient and elevated carbon dioxide(CO_(2)).Important FindingsOur results indicated that 8 of the 14 target parameters,such as C:N ratios in most ecosystem compartments,plant N uptake and external N input,were well constrained by available datasets whereas the others,such as N allocation coefficients,N loss and the initial value of mineral N pool were poorly constrained.Our analysis showed that elevated CO_(2)led to the increases in C:N ratios in foliage,fine roots and litter.Moreover,elevated CO_(2)stimulated plant N uptake and increased ecosystem N capital in Duke Forests by 25.2 and 8.5%,respectively.In addition,elevated CO_(2)resulted in the decrease of C exit rates(i.e.increases in C residence times)in foliage,woody biomass,structural litter and passive soil organic matter,but the increase of C exit rate in fine roots.Our results demonstrated that CO_(2)enrichment substantially altered key parameters in determining terrestrial C and N interactions,which have profound implications for model improvement and predictions of future C sequestration in terrestrial ecosystems in response to global change.
文摘甘薯是我国重要的粮食与经济作物,高氮环境下容易茎叶旺长而造成产量和品质的降低。本研究以不易徒长的品种徐薯32号和易徒长的品种徐紫薯8号为试验材料,设置不同施氮肥水平(0、80和200 kg hm–2)处理,测定甘薯徒长表型和碳氮含量变化,通过转录组测序进行相关代谢途径和徒长候选基因挖掘分析,并对测序结果进行RT-qPCR验证。结果表明,与徐薯32号相比,高氮处理下徐紫薯8号的地上部生长更加旺盛,块根产量显著降低,徒长情况严重。高氮处理使2个品种茎尖的氮含量增加而可溶性糖含量降低,碳氮代谢途径的基因表达量显著提高,徐紫薯8号茎尖的碳氮代谢变化更加显著,地上部易受高氮影响。转录组测序表明,正常施氮和高氮处理间存在差异表达基因3852个,对2个品种共同筛选到的1174个差异表达基因进行GO与KEGG通路富集分析,发现差异基因在损伤响应、茉莉酸响应、氨基酸代谢、玉米素生物合成等途径被显著富集,不同甘薯品种对高氮可能存在共同的响应机制。相同处理下,徐薯32号和徐紫薯8号间差异表达基因共6998个,对高氮处理筛选到而正常施氮未筛选到的1186个差异表达基因进行GO与KEGG通路富集分析,发现差异基因在类异戊二烯代谢、激素应答、细胞色素P450、氮代谢、玉米素生物合成等途径被显著富集,进一步筛选到6个甘薯高氮徒长的候选基因(g9506.t1、g14945.t1、g37255.t1、g25587.t1、g7821.t1和g18076.t1)。本研究为解析甘薯高氮徒长的生理机制提供了理论支持,也为选育耐高氮甘薯品种提供了基础。
